It's no secret that browser extensions can have a negative effect on memory usage. Mozilla has conducted some research that once again reiterates just how much RAM extensions like Adblock Plus can eat.

One Mozilla developer took a look at AdBlock Plus' effect on Firefox' RAM usage and found that for every ad the extension blocks, it uses up a little bit more memory. That accumulates for every ad on every site until the amount of space occupied by ads may be much higher than it is without the ad blocker:

Second, there's an overhead of about 4 MiB per iframe, which is mostly due to ABP injecting a giant stylesheet into every iframe. Many pages have multiple iframes, so this can add up quickly. For example, if I load TechCrunch and roll over the social buttons on every story (thus triggering the loading of lots of extra JS code), without ABP, Firefox uses about 194 MiB of physical memory. With ABP, that number more than doubles, to 417 MiB. This is despite the fact that ABP prevents some page elements (ads!) from being loaded.

That's a lot of RAM usage. It's also not exactly a huge surprise. Not only have we known for years that extensions can use up a ton of RAM, we've even found extensions that suspend extensions you haven't used recently to reduce RAM usage. You can make your own joke about irony below.

Of course, it should also be noted that Firefox (and Chrome, let's not leave anyone out) can also be a pretty big memory hog on its own without any extensions. The author of this post has said that he hopes Mozilla and ABP can work on reducing this particular memory load, but it's worth pointing out that no one is exactly blameless here. Browsers and extensions in general are natural resource hogs. But if you've been complaining about yours lately, it might be time to take a look at your extensions—specifically hungry ones like ABP.

That's not to say you shouldn't use those extensions, of course.. Some Lifehacker readers (and writers) swear by AdBlock (though we do ask that you whitelist sites you want to support, ahem). Others of us prefer to keep our browsers lean, since they're already pretty heavy.

What about you? Is blocking ads worth higher memory usage? Or do you not have the resources to spare? What are your best solutions for fixing your browser when it or its extensions grow unwieldy?